Motor actuated valve

Claim 1

A POWER ACTUATED VALVE COMPRISING, A CASING DEFINING A CHAMBER, PORTS FOR FLOW OF FLUID TO AND FROM SAID CHAMBER, AND AN ANNULAR VALVE SEAT; A CLOSURE MEMBER ADAPTED TO COACT WITH SAID SEAT FOR SELECTIVELY INTERRUPTING FLOW BETWEEN SAID PORTS; A SCREW THREADED STEM OPERATIVELY CONNECTED TO SAID CLOSURE MEMBER; A NUT HAVING A THREADED CONNECTION WITH SAID STEM AND SUPPORTED FROM THE CASING SO AS TO BE ROTATABLE ABOUT ITS AXIS FOR MOVING SAID STEM LONGITUDINALLY OF ITS AXIS; GUIDE MEANS ON SAID CASING AND STEM FOR RESTRAINING SAID STEM AGAINST ROTATION RELATIVE TO SAID CASING AND LIMITING MOVEMENT THEREOF TO LONGITUDINAL MOVEMENT TOWARD AND AWAY FROM SAID SEAT; A STOP MEMBER IN SAID CASING FOR LIMITING MOVEMENT OF SAID CLOSURE MEMBER AWAY FROM SAID SEAT; A MOTOR FOR TURNING SAID NUT; MEANS FOR OPERATIVELY CONNECTING SAID MOTOR TO SAID NUT AND ADAPTED TO ROTATE THE NUT IN ONE DIRECTION WHEN THE MOTOR IS ENERGIZED; A COIL SPRING OPERATIVELY CONNECTED TO SAID CASING AND NUT FOR ROTATING IT IN THE OPPOSITE DIRECTION WHEN SAID MOTOR IS DEENERGIZED; AND MEAN OPERATIVE WHEN THE MOTOR IS DEENERGIZED FOR RELEASING SAID NUT FOR ROTATION BY ENERGY STORED IN SAID SPRING.